| 摘要 |
PURPOSE:To enable production of calcium carbonate having an uniform shape and excellent water dispersibility in a short time, by feeding fine bubbles of gaseous carbon dioxide from a rotary gas diffuser pipe into an aqueous suspension of calcium hydroxide in a specific concentration in a reaction vessel. CONSTITUTION:An aqueous suspension of calcium hydroxide in 5-15wt.% concentration is filed in a reaction vessel equipped with a rotary gas diffuser pipe and fine bubbles of gaseous carbon dioxide are blown from the rotary gas diffuser pipe to carry out carbonation reaction. According to this method, variation in crystal form or particle size is small even if concentration and temperature of the aqueous suspension of calcium hydroxide, blowing rate of the gaseous carbon dioxide, concentration, etc., slightly fluctuate. Thereby calcium carbonate having excellent water dispersibility can be produced in a short time. Furthermore, if waste gas from lime kilns of pulp manufacturing plants is blown by the above-mentioned method, the aimed calcium carbonate useful as a paper filler coating pigment is obtained without using drying and disintegrating steps.
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